This invention is related to a new type of engine in which combustion is provided in a compression chamber between a fixed piston and a movable cylinder, both of the annular shaped type. It is well known in the prior art that it is possible by combustion of a fuel, liquid or gas, to provide a controlled expansion of gases in such manner as to provide movement of a piston in a cylinder and then provide a mechanical power take-off from the piston movement. A variety of engines are known in which gas and air are mixed and then ignited to provide the piston movement. In others, pre-mixed gas and air are compressed before ignition. These engines generally known by the term internal combustion engines require carefully controlled ignition of the fuel and rather complex lubrication and cooling systems in view of the high temperatures and the rapid reciprocating movements of the parts. In standard internal combustion engines, it is further necessary to provide a large number of exceedingly close tolerance parts so that the cost is high and in many cases the final product is not suitable because of its cost and weight for powering motor cars or the like.
In addition, internal combustion engines are most economical when using petroleum products such as gasoline or diesel oil. These fuels will become relatively scarce in the near future and hence will be more expensive. The present invention makes it possible to use a broad variety of fluid and gas fuels.
The prior art also has provided a great variety of gas turbine engines. The underlying principle of operation for such engines is to compress the air in a compressor, to inject the fuel to raise the temperature of the air, and finally to direct the hot air flow against the blades of a turbine wheel to give a rotational mechanical movement of the wheel and thus perform work. In some cases, separate engines are used for compressing the air, or a part of the power developed by the turbine is used for driving a compressor. A problem that always arises from turbines is that the hot air being used to impinge against the turbines allows only a limited number of materials to be used in forming the turbine blades because of the high temperatures involved. This makes the turbine engine both expensive and difficult to manufacture. An even more important consideration is that gas turbine engines typically use at least two thirds of the heat power generated in driving the compressor. This results in an efficiency for gas turbine engines of 25% at best.
The present invention will be seen to relate to an engine in which air cooling is provided in such manner that the rotating or reciprocating working parts are not subjected to excessively high temperatures, high pressures nor to the effects of hot expanding gases in such manner as to require expensive and heavy construction engine parts. To the contrary, the combustion of the fuel is used for initiating a two-cycle mode of operation of a cylinder and piston. The associated working parts are continuously air cooled and the compression chamber itself is subjected to a complete scavenging flow. The complete scavenging flow effect results in a virtually pollution-free engine with a cylinder and piston design which prevents concentrated hot spots. In this way, the formation of the polluting compounds of nitrogen is largely prevented.
The pressure from the fuel being combusted in the compression chamber between the movable cylinder and stationary piston is utilized in the following turbine stage in the combined engine version of my invention. There is provided a continuous cooling effect, particularly through the unique arrangement of ports in the movable cylinder. An even more significant feature of my invention is that there is allowed a purging of the compression chamber during the movement of the cylinder away from the piston such that there is provided an almost complete removal of incompletely combusted elements of the fuel. There is provided a lowering of temperature along with the removal of noxious substances to provide clean burning of each following fuel charge.
Viewed in its broadest aspect, the present invention provides a greatly improved and novel two-cycle type internal combustion engine of either the ignition system fired or the diesel type. It further combines such an engine with a gas turbine stage or stages such that the input of compressed air to the engine provides a continuous cooled driving effect to a turbine stage which is positioned in the engine outlet. The turbine stage is further in driven communication with the hot gases provided from firing of the fuel within the internal combustion engine compression chamber.